#pragma once
#include <string>
#include <set>
#include <iostream>

namespace html { namespace dom
{
  using namespace std;

  /// @brief class
  struct class_set : public set<symbol> {
    const class_set& operator+= (symbol _sym);
    const class_set& operator-= (symbol _sym);
    friend ostream& operator<< (ostream& _os, class_set _classes);
  };
} }
